The ancestors to modern humans really hit their stride 1.5 million years ago. Fossilized footprints found in Kenya were made by hominids that share a common foot anatomy and walking stride with modern humans, researchers say.
Scientists are almost certain that the 1.5-million-year-old prints belong to Homo erectus and that the individuals had heels, insteps and toes almost identical to those in humans, and they walked with a long stride similar to human locomotion…. The prints helped explain fossil and archaeological evidence that erectus had adapted the ability for long-distance walking and running [The New York Times]. There is evidence of a heavy landing on the heel with weight transferred along the outer edge of the foot, progressing to the ball of the foot and lifting off with the toes [BBC].
